Copper Awning - Off the Deep End

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Kriev
Posts: 8
Joined: Fri Feb 27, 2015 12:10 pm

Copper Awning - Off the Deep End

Unread post by Kriev » Mon Mar 02, 2015 8:44 am

Currently I am engulfed in a complicated project that I often feel is way above my current capabilities as a craftsman and sometimes feel that the growing pains might kill me. But I carry on knowing that somehow this will resolve itself (with persistence).

The basic is as follows, designed by the client: Two shelf-style brackets supporting a 3'x7' copper awning arch. No problem. The only problem is he went ahead and ordered the copper sheet to be paper thin.

So now I'm dealing with a change order to include a support structure between the brackets to hold the sheet from flopping.
I didn't incorporate any way of adding to the brackets.

The support will be a long piece of angle-iron supporting the front edge of the awning. Another strap will provide extra support to the midsection of the sheet. This strap will pass through a "spine" the joins to both the angle iron and to the house.

So I've gone ahead and started the support structure, all the while wondering how I'm going to rivet this awning to the brackets AND the angle iron, making sure it all fits together.
Attachments
Brackets Mounted.JPG
Brackets Mounted.JPG (4.18 MiB) Viewed 2129 times
brackets mounted side.JPG
The horizontal bar is slanted at a 45 degree angle.
brackets mounted side.JPG (3.05 MiB) Viewed 2129 times

Martin Pansch
Posts: 311
Joined: Thu Feb 14, 2013 10:44 am
Location: Young America, MN

Re: Copper Awning - Off the Deep End

Unread post by Martin Pansch » Mon Mar 02, 2015 1:38 pm

Hi Kriev.

You have to love those "rapid design change" issues like this. We, maybe after you are successful with it you have to love it. At the time it is a pain in the tuchus.

How close is the copper to final dimensions? Is there some extra length or width? On of the tricks industry uses to give more rigidity to thin, flimsy sheet metal is to put some ridges in it. Done right it could add to the design as well. Years ago Chris Rand demonstrated doing this with some hand held air impact hammers with some custom repousse tool ends. If it is really thin like you say that might be overkill and working it by hand might be easy enough work with a couple simple custom tools. Of course if the client did the design they might not like that change but is it something that could be suggested. Of course if the copper was ordered that thin I am guessing it was ordered EXTACTLY the final dimension too to save costs.

Attaching the steel brackets and copper sheet is going to be another trick. Putting copper and steel in direct contact is a good way to demonstrate galvanic corrosion. Looking around Wikipedia shows that the Statue of Liberty used a copper saddle over the iron support piece. An insulator was placed between the saddle and iron, originally shellac but with the rebuild PTFE was used. The copper saddle and copper skin were fastened together with copper rivets. I know that Chris Rand is now working a lot of copper and bronze so maybe we can get his input on ways of attaching copper to steel.

Good luck and please update your post as you progress and solve the problems thrown in your way.

Kriev
Posts: 8
Joined: Fri Feb 27, 2015 12:10 pm

Re: Copper Awning - Off the Deep End

Unread post by Kriev » Mon Mar 02, 2015 8:04 pm

I have some nylon cutting boards set aside for riveting the between the copper and steel. The client too expressed… "well I'm not gonna last THAT long… as long as it lasts like 30 years." What this points to us is to not let a non-blacksmith design a project for us.

Good suggestions, Martin. But like you said the dimensions don't allow the corrugating. I did try to stiffen the sheet by cutting and riveting the sheet and a few passes of a rounding hammer on a log.

Its satisfying to have done the brackets up. However, this change up adds a whole new dimension of challenge. And for that I should be grateful. But at the moment I feel a bit like a construction foreman without a crew. It seemed manageable to rivet just to the two horizontal bars.

However, I've made some progress with the support. I found in my Francis Whitaker Cookbook, a recipe for bending angle iron. You start be doing a pre-bend in the opposite plane that is 3 times the desired radius. Then when you do the final bend, you get a nice curve without distortion.
Attachments
final bending.JPG
now the final radius in progress (36")
final bending.JPG (2.74 MiB) Viewed 2119 times
final bend in progress.JPG
final bend in progress.JPG (3.28 MiB) Viewed 2119 times
pre-bend.JPG
The pre-bend radius of 108"
pre-bend.JPG (3.12 MiB) Viewed 2119 times

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